Ofsted's authority to sit in judgment on teachers should be held to question, claims a Birmingham head who has fought for three years against a botched report on her school.
Jane Hattatt is demanding the organisation publicly apologises for publishing the inaccurate document on Lordswood Girls' School, which has been re-written.
She challenged Ofsted after finding parts of the report were directly lifted from another less successful school 100 miles away.
The document was also found to contain incorrect judgments on seven other key areas of performance. The education watchdog said it regretted the delay in setting the record straight.
However, Ms Hattatt said: "For three years people have read levels of standards at this school wrongly.
"The person who did this inspection did a shoddy job. Parents and everyone else place a lot of faith in these reports. If they are going to be credible, they have to be accurate, at least.
"It raises the question of how much faith we can have in Ofsted."
Inspectors visited the school in November 2003. Ms Hattatt became suspicious when the report was published in January 2004 because it contained judgments on areas she knew had not been inspected.
Further investigation revealed comments made under the leadership and management section were identical to those in a report on Parkside School in Bradford, West Yorkshire.
Ofsted accepted the inspection team had failed in its duty to give an accurate and fair portrayal of Lordswood. It promised to amend the report and update its website.
However, when the changes failed to materialise, Ms Hattatt went to the next stage in Ofsted’s complaint procedure and contacted the independent adjudicator.
A report by the adjudicator published last year backed Ms Hattatt and urged the inspection body to take "all possible steps to ensure that a full and accurate addendum is prepared without further delay".
When that did not happen, Ms Hattatt contacted the Parliamentary Ombudsman this February. Ms Hattatt said the Ombudsman claimed it could not take the matter any further.
Last week, however, Ofsted finally offered a new report including a rewritten leadership and management section. The achievement of pupils was changed from "good" to "outstanding" and six other judgments on standards upgraded from "good" to "very good".
Lead inspector David Bate has since resigned from VT Education Consultants, which carried out the inspection.
Ms Hattatt said: "If there is a bad school, there are plenty of things that happen. But when there is a bad inspection it seems we don’t have any procedure."
A spokeswoman for Ofsted said: "Ofsted takes all complaints very seriously. We regret it took so long to resolve this matter while the complaint went through the normal procedures."
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